project euler solution for #36

1 files changed, 40 insertions, 0 deletions

diff --git a/src/projecteuler/036.py b/src/projecteuler/036.py
new file mode 100644
index 0000000..bf800da
--- /dev/null
+++ b/src/projecteuler/036.py
@@ -0,0 +1,40 @@
+
+binary = [ 2**x for x in range(20) ][::-1]
+
+def palindromic_decimal(n):
+	if n == int(str(n)[::-1]):
+		return True
+	return False
+
+
+def dec2bin(n):
+	res = ""
+	for i in binary:
+		if n - i > 0 or n == i:
+			res += "1"
+			n -= i
+		else:
+			if len(res) > 0: # do not add leading 0s
+				res += "0"
+	return res
+
+def bin2dec(n):
+	res = 0
+	for i in range(1, len(n)+1):
+		if n[-i] == "1":
+			res += binary[-i]
+	return res
+
+def palindromic_binary(n):
+	if n == bin2dec(dec2bin(n)[::-1]):
+		return True
+	return False
+
+sum = 0
+
+for n in xrange(1000000):
+	if palindromic_decimal(n) and palindromic_binary(n):
+		sum += n
+
+print sum
+